The danger of exposure to chemical or biological agents can be severe. Whether a result of unintended release by way of, e.g., an accident, or a result of intentional delivery, it is desirable to quickly and accurately identify (1) the type of agent that has been released and (2) the precise area of contamination. Early and accurate detection of such dangerous substances can be a significant factor in reducing potential casualties and limiting further spreading of the agent by, e.g., wind, human or animal contact, among other transmission mechanisms.
In recent years, there has been an increased interest in developing and deploying sensor technologies to quickly identify unknown substances, contaminants, and agents, even at very low concentrations. Some of these technologies are designed to measure surface-deposited contamination using vehicles and associated test equipment to retrieve a physical sample of the contaminant and then employ extremely cumbersome and time-consuming processes based on a mechanical sampling wheel system to test for agents.
In view of the complexity of such approaches, newer, safer and more reliable technologies have emerged. One such technology is referred to, generally, as “standoff surface detection,” and refers to a category of technologies that permit detection of substances without actually having to physically come in contact with the substance or agent of concern. The goal of these detection systems is to provide the capability to detect, identify, locate, quantify, warn, and report chemical or biological threats and thereby give military forces or civilian personnel sufficient early warning to avoid (further) contamination.
An example of a standoff surface detection system is a technology known as Laser Interrogation of Surface Agents (LISA) that has been developed by ITT Industries, Inc. (Wilmington, Del.). In one implementation, LISA uses a laser and associated sensor, attached to a reconnaissance vehicle such as a truck or HMMWV, that looks for chemical agents on the ground (or any surface) using a technique known as Raman Scattering (or Raman Effect, or Raman Spectroscopy analysis), which is an optical property that can be exploited to identify chemical and biological agents. One particular implementation of LISA has a 1.5-meter standoff range and can provide detection on each single laser shot or pulse, at, e.g., 25 pulses per second. This gives personnel manning the vehicle the ability to perform on-the-move, real-time detection of chemical agents on the ground. This on-the-move detection is characterized by single-event detection because each laser shot is a separate event that can produce a detection decision by the sensor and each laser shot is independent of past or future laser shots. The LISA technology also provides the ability to create or generate a position detection map with inputs from, e.g., GPS, with chemical agent contours that build up as detection is taking place.
Standoff biological agent detection is significantly more difficult than chemical detection. Specifically, it is often difficult to discriminate and measure biological agents from naturally occurring background materials. Moreover, real-time detection and measurement of biological agents in the environment can be daunting because of the number of potential agents to be identified, the complex nature of the agents themselves, the countless number of similar microorganisms that are a constant presence in the environment, and the minute quantities of pathogen that can initiate harmful reactions. Potential biological agents can also disguise themselves in benign entities.
In light of these and other obstacles and in furtherance of more accurate contaminant detection capabilities, there is still a need for improvements in stand-off on-the-move detection systems.